$ DOCKER_USERNAME=***
$ DOCKER_PASSWORD=***
​
$ kubectl create secret docker-registry registry-credentials \
    --namespace default \
    --docker-username=$DOCKER_USERNAME \
    --docker-password=$DOCKER_PASSWORD
​
$ kubectl patch serviceaccount default --namespace default \
    -p "{\"imagePullSecrets\": [{\"name\": \"registry-credentials\"}]}"

$ kubectl delete secret --namespace default registry-credentials
​
$ kubectl patch serviceaccount default --namespace default \
    -p "{\"imagePullSecrets\": []}"